Laundry drier



March 30,1943.

J. D. SHANMAN LAUNDRY DRIER Filed April 11, 1940 3 Sheets-Sheet 1 INVENTORZ ,ZZS/Ianmmz March 30, 1943. J. D. SHANMAN LAUNDRY DRIER Filed April 11, 1940 3 Sheets-Sheet 2 m T .N WWW mm m h Patented Mar. 30, 1943 UNITED STATES PATENT OFFICE V LAUN l rnlER I Jerome D. ShanmamClncinnatl, Ohio Application April 11, 1940, Serial No. 329,067

1 Claim.

The invention relates to laundry driers, and more particularly to warm air driers of the type in which a flow of air is produced by induction.

One of the most successful types of commercial laundry driers has been that in which warm air is drawn over and through the clothes or other articles to be dried while these articles are being tumbled in a rotating drum. In one well-known drier of this type the down-draft principle is employed, the air being drawn in through an adjustable damper at the top of the machine, and then passing over heating coils on its way to the drying cylinder. The operation of such a machine involves the induction of a large quantity of air at only. moderately high temperatures, and produces a most efiicient and rapid drying action.

When such a machine is operated in a locality where there is a substantial amount of soot in the atmosphere, as in industrial cities, it becomes desirable to filter the air before permitting it to enter the drier. When, however, it is attempted to employ filter elements at the air intake of machines of the class described, difiiculty is experie'nced in creating the desired rate of air flow because of the resistance of the filter. I have found, however, that if a filter element is placed at a substantial distance away from the intake plate or damper, with an enclosed chamber of considerable volume therebetween, this difficulty can be overcome. I have also discovered that such an arrangement produces a surprising decrease in the length of timerequired to dry a load of garments. This I attribute to the pre-heating effect produced by the chamber between the filter element and the heating coils. Thus the chamber and filter unit not only creates a reserve air also increases the efficiency of the drier. Before the tumbler and induction fan are started, and

also during the intervals that they are stopped for loading and unloading, initial or residual heat in the pipe coils or other heating element is transf erred to the air in the filter chamber, conserving a portion .of heat that would otherwise be lost, andalso decreasing the drying time for the next batch.

Accordingly, it is an object of my invention to provide an induction drier having air filtering means so arranged as not to unduly restrict the air intake or interfere with the operation of the air intake control damper, while at the same time providing a pre-heating chamber for the air.

Another object is to provide means for increasing the efiiciency of operation of the induction space, decreasing resistance to the air flow, but

drier with portions broken away in transverse vertical section.

Fig. 3 is a top plan view of the main part of the drier with some of the filter pads removed and other parts broken away to show the construction of the air intake damper mechanism.

Fig. 4 is a v'ertical longitudinal sectional view through the upper part of the machine, taken substantially on the line 4-4 of Fig. 3.

The drawings illustrate a preferred embodiment of my invention as applied to a down-draft induc-- tion drier in which the air is drawn through an intake controlled by a slotted plate type of damper. However, the invention is applicable to other types of induction driers, and to driers having other forms of air intake control means.

Referring particularly to Figs. 1 and 2, the drier which I have selected for the purpose of illus- I tration will be seen to consist, in its general organization, of a drying cylinder or drum i in which a cylindrical perforated tumbler'is rotatably mounted in any convenient manner, an air heating chamber 2, an air outlet duct 3, and an exhaust fan 4. The perforated tumbler is designed to hold the clothes or other articles which are to be dried, and may be of any suitable construction. Inasmuch as tumblers of this character are well known in the art to which the present invention pertains, it is not considered necessary to illustrate or describe the details of its construction.

The drying cylinder l is supported by lower frame members 5 having semi-circular cradles 8. The cradles 6 of the end frames 5 are flanged, as at 1', for connection to flanges 8 formed on the semi-circular bands 9 of upper frame members Ill. The upper frame members lllcarry the air heating chamber 2 within which are supported suitable heating elements such as the pipe coils irons l3 one leg of which is secured to the wall.

of chamber 2, the other leg being secured to. a flange l4 formed on the wall of chamber I2. Transverse supporting bars I5 are bolted or otherwise secured to the angle irons 13 at spaced intervals, these bars being notched to receive, in spaced relationship, aseries of longitudinal bars l6. Above the bars l6 are slidable damper plates I! which are provided with openings I8 50 arranged that in one position 01' the plate they will overlie the bars it, but that in another position they will be aligned with the spaces between those bars. Adjustment of the damper plates to control the area of the air intake to the chamber 2 may be effected through a hand lever l9 secured to a shaft supported in bearings associated with the chamber l2, the shaft 23 having arms 2| keyed thereto for operating the plates I! through connecting rods 22 pivotally secured at one end to arms 2|, and at the other end to a bracket 23 fastened to the plate II, or to a brace 24 which in turn is secured to the plate. When the handle is is in the position shown in full lines in Fig. 2, the maximum air intake area is provided. When it is in the position shown in dot-dash lines at 25, the air intake is entirely closed. At intermediate positions of the handle,

various air intake areas are provided. It will be understood that other forms or damper construction could be employed ii! desired, and in some instances the damper might be eliminated altogether.

In the form of drier illustrated, the cylinder door 23 which is pivotally mounted to the cylinder at 21 is counterbalanced by weights 28 to which the door is connected by flexible cables 23 passing over the top of the heating chamber 2 on pulleys 30, 3|. Where these cables 29 pass through the pre-heating chamber i2, I provide tubes 32 to seal this chamber. By providing these tubes 32 it becomes possible to apply my preheating chamber and filter unit to existing types of driers in which the door supporting cables extend over the top of the heating chamber, without the necessity of replacing or altering the counterbalance mechanism.

At the entrance to the pre-heating chamber i2 there is arranged a filter element which preferably is in the form of pads 33 made of spun glass, but which may be made of other suitable materials. I have mounted these pads on brackets 34, and 36 secured to the inner wallsof the chamber I2. As shown, the brackets 34 consist oi! angle irons,and the brackets35 and 36 consist of fianged plates dividing the upper end of the chamber l2 into a series of filter compartments. The brackets together form a continuous support around the periphery of the pads so as to prevent by-passing of air around the edges thereof. The construction described also permits ready removal: of the filter pads for cleaning. Proper relationship between the area of the pads 33 and the openings in the slid plate I! is obtained by making the width of the pads (transversely of the machine) less than the width of the chamber 2.

Other elements disclosed in the drawings, but

which may be of any well-known construction and therefore need not be described in detail, are the pivoted unloading shelves 3'! (Fig. l) which can be swung into position to bridge the space between the cylinder l and perforated tumbier when the door 26 is open. the gears 38, 39,

40 which transmit power from the belt and pulley ll, 42 to the tumbler, the exhaust fan housing 43, the duct 44 connecting the fan housing to outlet duct 3. and the motor 45 which forms a suitable prime mover for the exhaust fan.

In operation, the fan 4 creates a suction in the drier which induces a flow of air in through the filter pads 33, chamber l2, and damper l6, H, at which point the air passes into the heatin: chamber 2 and over and through the heating coils Ii therein. The heated air is then drawn through the cylinder l in which the clothes are dried, preferably while being tumbled n a rotating drum, and the moisture-laden air finally passes out through the ducts 3 and 44, and is discharged by the fan I. The chamber l2, located as it is between the heating chamber 2 and filter 33, provides a reserve air space which permits the filter to operate at maximum efliciency and overcomes the diillculties which were encountered when the filter was placed adjacent the damper l6, I1. I have found, moreover, that in commercial operation of a drier constructed in accordance with my invention, the use of the filter and reserve air chamber unit decreased the length of time required to dry the clothes. This seems surprising in view of the fact that no heating coils were added, and 'that 'no heating coils were used in the reserve air chamber i2. This result might be explained by assuming that the filter and reserve air chamber unit prevent the lossoi' a certain amount of heat by direct radiation upwardly. and also may be partly explained by the prevention of loss of initial or residual heat by both convection and conduction before the tumbler and induction ian are started. and during the intervals that they are stopped for loading and unloading. During the loading and unloading intervals it would often be undesirable to close the damper to conserve heat, as this would be likely to cause overheating which i sometimes scorches the soap and produces an offensive odor. Yet with my arrangement the initial or residual heat can be utilized to warm a reserve air supply, and overheating is avoided by the presence of the filterpads which, when the tan is not operating, will allow excess heat to escape. While I have advanced certain theories to explain the increased efliciency of operation of the drier with respect to decreasing the drying time per load, I do not wish to be limited in this respect as it is possible that improvements are obtained for other reasons, or for reasons additional to those I have suggested.

Inasmuch as the present inventions is conconcerned primarily with thearrangement of a filter unit at the intake of an induction drier in a particular manner, and is not concerned with the details of construction or the drier itself, it will be apparent that other drier constructions could, be substituted for that specifically described so long as the relationship defined in the appended claim is maintained. The terms and expressions which I have employed are used as terms of description and not of limitation, and I have no intention of excluding such equivalents of the invention set forth, or of portions thereof, as fall within the purview of the claim.

I claim: I

A filter attachment for down-draft driers having an air intake at the top thereof, comprising a chamber for attachment above the air intake, a filter element, means for supporting the filter element in the upper part of the chamher, and a tube extending across the chamber to provide a passage therethrough which is sealed off from the chamber to accommodate part of the drier mechanism while preserving a fully enclosed air space between the filter element and the air intake for the drier.

JEROME D. SHANMAN. 

